Assessing Traffic Flow and Motorcyclist Safety Outcomes Associated with Lane Filtering

There is a significant gap in research examining how motorcyclists and drivers behave when motorcyclists lane split and/or lane filter in live traffic environments, and safety outcomes associated with lane splitting and lane filtering. Motorcycle lane splitting involves riding between lanes of slow-moving or stopped traffic. Lane filtering is the practice of a motorcyclist moving between lanes of stopped or slow-moving traffic to move to the front of the queue, typically at intersections or during heavy congestion. These practices are legal in some states, prohibited in others, and ambiguously defined in others. Motorcycle safety advocates and motorcyclist rights groups frequently cite safety benefits associated with lane splitting and lane filtering, while law enforcement agencies and traffic safety organizations raise concerns regarding increased risk and operational conflicts. These discussions often rely on limited domestic research, most notably a single observational study conducted in California, as well as studies conducted outside the United States. International research provides useful context but is limited in its applicability to U.S. traffic environments. U.S. decision-makers are often required to extrapolate from non-comparable data sources, contributing to inconsistent definitions and interpretations of these practices. Developing a better understanding of real-world interactions between motorists and motorcyclists, and safety outcomes associated with motorcycle lane splitting and lane filtering is critical for the development of effective driver training curricula and public education campaigns. The objectives of this research are to: 1. Document the existing state of knowledge regarding the impact safety outcomes associated with motorcycle lane splitting and lane filtering; 2. To support development of standardized, behaviorally grounded definitions to reduce ambiguity and improve consistency in policy and practice, conduct a multi-state observational study to understand interactions between motorists and motorcyclists during lane-splitting and lane-filtering; 3. Develop an evidence-based toolkit for use by state highway safety offices, state driver licensing agencies, and state motorcycle safety programs to manage the behavioral and safety complexities of motorcycle lane splitting and filtering.

• Record URL:
  • http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=6089

Language

• English

Project

• Status: Proposed
• Funding: $500,000.00
• Contract Numbers:

  BTS-50

• Sponsor Organizations:

  Behavioral Traffic Safety Cooperative Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001

  Governors Highway Safety Association

  444 N. Capitol Street, NW, Suite 722
  Washington, DC  United States  20001

  National Highway Traffic Safety Administration

  1200 New Jersey Avenue, SE
  Washington, D.C.  United States  20590
• Project Managers:

  Retting, Richard

• Start Date: 20261001
• Expected Completion Date: 0
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Driving behavior; Motorcycling; Traffic lanes; Traffic safety; Vehicle mix
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors;

Filing Info

• Accession Number: 01994963
• Record Type: Research project
• Source Agency: Transportation Research Board
• Contract Numbers: BTS-50
• Files: TRB, RIP
• Created Date: Jul 2 2026 7:30PM